underprop

/ˌʌndərˈprɑp/
verb
  1. To support or prop up from beneath, often to prevent something from falling or collapsing.
    • Engineers underpropped the bridge with steel pillars during repairs.
    • The miners used wooden beams to underprop the tunnel ceiling.
    • We had to underprop the old shed's floor before it caved in.
Antonyms
What does "underprop" mean? | whatsthatwordmean | whatsthatwordmean